As children, our creativity was bounded only by the duration and depth of our attention at any given moment.
As adults, our creativity is bounded not only by the quality of attention but also our specific evaluation of the worth and personal enjoyment interaction with a system might generate.
To put it simply, adults achieve consistent episodes of childlike creativity in those undertakings which they believe to be appropriate for their competencies, and most of all worthy of extended commitment of time.
The most helpful deficiency of the immature brain is its inability to schedule and manage time. This removes a distractor and allows for profound engagement with systems that would not even be noticed by someone who had a conception of places to be and important things to accomplish.
A child can spend several hours working on chalk drawings because every child has no reason to doubt their own competence in the art, and the worth of their works. They approach the sidewalk with the same confidence and excitement as the professional adult sculptor goes to the clay. In this way, the minds of the novice child and the adult master are the same.
In attempting to cultivate states of intense creativity, we must first believe in the value of whatever we might make. Otherwise, hours spent at the canvas will seem a waste of time, and thus those hours will not be spent, making mastery impossible.